From Wiktionary, the free dictionary
Unclear. Probably from demonstrative *sa + an unclear suffix, possibly an earlier *-no or *-ne . But it could also continue Proto-Indo-European *tóm , whence also Latin tum .
*þan
then , at that time
Proto-West Germanic: *þan Old Frisian: than Saterland Frisian: dan , do West Frisian: dan Old Saxon: than Old Dutch: than Middle Dutch: dan Dutch: dan ( “ then, than ” ) Old High German: dan
Proto-Norse: *ᚦᚨᚾ ( *þan )
Old Norse: þá ( “ then ” ) Icelandic: þá Faroese: tá Norwegian Nynorsk: då Old Swedish: þā Swedish: då , tå ( obsolete ) Danish: da
Old Norse: an ( “ than ” ) ⇒ Old Norse: en Icelandic: en Norwegian Nynorsk: enn Norwegian Bokmål: enn Old Swedish: æn Danish: end
Gothic: 𐌸𐌰𐌽 ( þan , “ then ” )